U.S. Rep. Marsha Blackburn (R-TN) has announced her bid for U.S. Senate in Tennessee in order to replace outgoing Sen. Bob Corker.

Blackburn is expected to receive the backing of conservatives with close ties to the Trump administration, such as David Bossie of Citizens United and Steve Bannon of Breitbart News. She is also reportedly favored by the fiscally conservative Club for Growth. Her main opponent is likely to be U.S. Rep. Stephen Fincher, after Gov. Bill Haslam announced that he will not run for the open seat. Fincher’s decision to run will likely determine whether the Koch brothers, who are said to be strongly opposed to a theoretical Fincher candidacy, decide to get behind Blackburn.

Although Blackburn usually aligns with Republican leadership in Congress, she is generally seen as leaning more towards the right of her party, boasting 88% scores from  FreedomWorks and Heritage Action. She served as a vice chair on President Trump’s transition team, and is portraying herself as a reliable vote for the Trump agenda if elected. This presents a sharp contrast with Corker, who after failing in his attempts to become Vice President and Secretary of State, has emerged as a vocal critic of the President. Recently, Corker threatened to join Sen. Rand Paul (R-KY) in opposing the administration’s tax plan, albeit for different reasons.

Blackburn has served as U.S. Representative from Tennessee’s 7th district since 2003. Her decision not to run for re-election and instead pursue a Senate seat opens the door for State Sen. Mark Green, a hardline conservative, to succeed her in the U.S. House of Representatives. Green has issued a statement confirming his intended bid, and is said to have the support of Bannon. If elected, Green would be likely to receive the backing of the Freedom Caucus.